' 
116 STORRS AGRICULTURAL EXPERIMENT STATION. 
the time which has elapsed since the last meal was taken, (2) 
the muscular activity of the subject, whether at rest or at work, 
(3) the external temperature, (4) the age and body weight, 
and (5) individual peculiarities of the subject. The accuracy 
with which the carbon dioxid eliminated for a given period 
measures the production for that period depends upon the 
so-called ‘‘lag’’ in the elimination, a topic to be discussed in 
another place. . 
In the experiments here considered there are considerable 
fluctuations in the output. Of the factors which cause these 
fluctuations the most important is the muscular activity. The 
differences in the food were. mainly those called for by the 
differences in the muscular exercise. The external tempera- 
ture, i. e., that of the air in the chamber, was kept as near to 
20°C. asconvenient. ‘The subjects were young, healthy, active 
men, of similar age, height, and weight, but differing slightly 
in the amounts of food to which they were accustomed, so 
that there was nothing to imply differences in personal charac- 
teristics so great as to effect materially the oxidation of carbon. 
The figures for the daily elimination of carbon dioxid are 
summarized in ‘Table 27, which shows the average amount 
per hour during each period and for the whole day, and the 
percentage which the output for each period makes of the 
average amount for twenty-four hours. 
The elimination of carbon dioxid under conditions of rest 
averaged 796 grams per day, or 33.2 grams per hour, in the 
twenty-five experimental days of the seven experiments with HE. 
_O.; 797 grams per day, or 33.2 grams per hour, in the three 
experimental days of one experiment with A. W..S.; andig62 
grams per day, or 31.8 grams per hour, in the nine experimen- 
tal days of three experiments with J. F..S. The range was 
from 739 to 879 grams per day with E. O., from 787 to 816 
with A. W. S., and from 715 to 801 with J. F.S. It will be 
remembered, however, that the experiments with H. O. were 
made at different times during two years, while with A. W. 5S. 
there was but a single experiment. ‘rhe experiments with J. 
F. S. were made at short intervals during one year. In eight 
experimental days of the two experiments in which the subject 
E. O. was engaged in active muscular work, for eight hours. 
each day the output averaged 1,316 grams per day, or 54.8 
